This is not very famous Quake 2 source port but it's surely one of the most advanced and best-looking. The range of supported effects is very high: dynamic shadows for monsters/objects, advanced lightning, motion blur, wall decals, lens flares, bloom, shader refraction for explosions and water, high-resolution textures support, nice particle systems effects for realistic explosions smoke, rocket trails and blood.
Download port installation file and run it to start setup process.
Ensure to check all needed components if you are using official addons with your Quake.
When installation asks you to choose the installation path, make sure that you change it to the directory with original Quake 2 files ('E:\games\Quake II' in my case).
Ensure to install OpenAL drivers for the in-game sound engine in the end of the installation.
Start the game by running 'quake2xp.exe' file. Open 'Video' from the main menu. Set the relevant 'Screen Resolution', set the 'Texture Anistropy Level' to maximum value, set 'Flares' to 'Volumetric', turn on 'Refractions', 'Shadows', 'Motion Blur' and 'Light Blooms'.
Open 'Video' -> 'Advanced Settings'. Turn on all three types of shadows, ensure to set 'Motion Blur Strength' to minimal value, turn on 'Underwater Caustics' and set 'Draw Sun' to 'full'. You can also experiment with the 'Bloom' settings, but I advise you to leave them by default or change them according to the screenshot.
Open 'Options' -> 'Advanced Settings' from main menu. Ensure that 'Enable Blood and Gore' and 'Enable Decals' have been turned on. I also advise you to try to play using the 'Third Person View'.